1. Field of the Invention
This invention relates to a wrapping paper defect inspection apparatus incorporated in a cigarette manufacturing machine, and more particularly, to a wrapping paper defect inspection apparatus which is capable of real-time detection of defects, such as pinholes, in elongate wrapping paper continuously supplied to a wrapping section for wrapping shredded tobacco therein and which is suited for rejecting defective cigarettes from among the cigarettes manufactured by cutting a tobacco rod having the shredded tobacco wrapped in the wrapping paper to cigarettes of predetermined length.
2. Description of the Related Art
In a cigarette manufacturing machine, cigarettes are manufactured by feeding shredded tobacco onto elongate wrapping paper continuously supplied to a wrapping section, wrapping the shredded tobacco in the wrapping paper to form a tobacco rod, and then cutting the tobacco rod to cigarettes of predetermined length. Also, a filter is attached to one end of each cigarette cut from the tobacco rod. In this type of cigarette manufacturing machine, the speed of wrapping shredded tobacco shows a tendency to increase.
The quality of wrapping paper affects the flow of air in cigarettes and has an influence upon the combustibility and taste of cigarettes. If, for example, the wrapping paper of a cigarette has a smaller thickness in part thereof or has a pinhole of about 1 mm in diameter therein, the flow of air in the cigarette is liable to change when the cigarette is smoked. To manufacture high-quality cigarettes, therefore, it is necessary that the quality of the wrapping paper be carefully controlled.
The wrapping paper, which is at first in the form of a paper roll and is elongate with a width of about 27 mm, for example, is unrolled to travel at high speed along a predetermined transportation path and is continuously supplied to the shredded tobacco wrapping section of the cigarette manufacturing machine. It is therefore difficult to detect defects in the wrapping paper, such as pinholes, without fail.
Specifically, defects in the wrapping paper need to be detected on a real-time basis while the wrapping paper is caused to travel at a high speed matching the shredded tobacco wrapping speed. However, since the wrapping paper traveling at high speed is liable to sway in the width direction, it is difficult to detect defects such as pinholes with high accuracy. Such sway of the wrapping paper may be suppressed by controlling the supply (travel) of the wrapping paper with high accuracy, but this requires the use of equipment considerably large in scale and complicated in structure.